----------------------------- MODULE ServiceLayer ------------------------------

EXTENDS Naturals, Sequences, FiniteSets, MemoryManager, CapabilitySystem

(*
 * ZENrs 服务层与exokernel交互形式化模型
 * 
 * 本模型描述了ZENrs服务层（使用Rust语言安全部分实现）与exokernel（使用Zig语言实现）之间的交互，
 * 用于验证系统的整体安全性、资源隔离和并发安全性。
 *)

(* 导入MemoryManager和CapabilitySystem模块的定义 *)
MemoryManagerState == MemoryManager!MemoryManagerState
CapabilityManagerState == CapabilitySystem!CapabilityManagerState
CapabilityId == CapabilitySystem!CapabilityId
PhysicalAddress == MemoryManager!PhysicalAddress
VirtualAddress == MemoryManager!VirtualAddress
MemoryPermissions == MemoryManager!MemoryPermissions

(* 服务类型 *)
ServiceType == {"memory", "process", "filesystem", "network", "graphics", "vulkan", "skia", "wayland", "ipc", "kuikly"}

(* 服务状态 *)
ServiceState == [
    id : Int,
    type : ServiceType,
    running : Bool,
    capabilities : Set(CapabilityId)
]

(* 服务管理器状态 *)
ServiceManagerState == [
    services : Seq(ServiceState),
    next_service_id : Int
]

(* 系统状态 *)
SystemState == [
    mm_state : MemoryManagerState,
    cm_state : CapabilityManagerState,
    sm_state : ServiceManagerState
]

(* 初始状态 *)
Init == 
    [
        mm_state |-> MemoryManager!Init,
        cm_state |-> CapabilitySystem!Init,
        sm_state |-> [
            services |-> << >>,
            next_service_id |-> 1
        ]
    ]

(* 创建新服务 *)
CreateService(ss, service_type) == 
    LET
        service_id == ss.sm_state.next_service_id
        new_service == [
            id |-> service_id,
            type |-> service_type,
            running |-> FALSE,
            capabilities |-> {}
        ]
        
        new_services == Append(ss.sm_state.services, new_service)
        
        new_sm_state == [ss.sm_state EXCEPT 
            !services = new_services,
            !next_service_id = ss.sm_state.next_service_id + 1
        ]
    IN
        [ss EXCEPT 
            !sm_state = new_sm_state
        ]

(* 启动服务 *)
StartService(ss, service_id) == 
    LET
        found_service == CHOOSE i \in DOMAIN ss.sm_state.services : 
            ss.sm_state.services[i].id = service_id
        
        (* 更新状态 *)
        new_services == IF found_service # "" THEN 
            ReplaceAt(ss.sm_state.services, found_service, 
                [ss.sm_state.services[found_service] EXCEPT !running = TRUE])
        ELSE 
            ss.sm_state.services
        
        new_sm_state == [ss.sm_state EXCEPT 
            !services = new_services
        ]
    IN
        [ss EXCEPT 
            !sm_state = new_sm_state
        ]

(* 停止服务 *)
StopService(ss, service_id) == 
    LET
        found_service == CHOOSE i \in DOMAIN ss.sm_state.services : 
            ss.sm_state.services[i].id = service_id
        
        (* 更新状态 *)
        new_services == IF found_service # "" THEN 
            ReplaceAt(ss.sm_state.services, found_service, 
                [ss.sm_state.services[found_service] EXCEPT !running = FALSE])
        ELSE 
            ss.sm_state.services
        
        new_sm_state == [ss.sm_state EXCEPT 
            !services = new_services
        ]
    IN
        [ss EXCEPT 
            !sm_state = new_sm_state
        ]

(* 授予服务能力 *)
GrantCapabilityToService(ss, service_id, cap_id) == 
    LET
        found_service == CHOOSE i \in DOMAIN ss.sm_state.services : 
            ss.sm_state.services[i].id = service_id
        
        (* 检查能力是否存在 *)
        cap_exists == \E c \in ss.cm_state.capabilities : c.id = cap_id
        
        (* 更新状态 *)
        new_services == IF found_service # "" /\ cap_exists THEN 
            ReplaceAt(ss.sm_state.services, found_service, 
                [ss.sm_state.services[found_service] EXCEPT 
                    !capabilities = ss.sm_state.services[found_service].capabilities \union {cap_id}])
        ELSE 
            ss.sm_state.services
        
        new_sm_state == [ss.sm_state EXCEPT 
            !services = new_services
        ]
    IN
        [ss EXCEPT 
            !sm_state = new_sm_state
        ]

(* 从服务收回能力 *)
RevokeCapabilityFromService(ss, service_id, cap_id) == 
    LET
        found_service == CHOOSE i \in DOMAIN ss.sm_state.services : 
            ss.sm_state.services[i].id = service_id
        
        (* 更新状态 *)
        new_services == IF found_service # "" THEN 
            ReplaceAt(ss.sm_state.services, found_service, 
                [ss.sm_state.services[found_service] EXCEPT 
                    !capabilities = ss.sm_state.services[found_service].capabilities \ {cap_id}])
        ELSE 
            ss.sm_state.services
        
        new_sm_state == [ss.sm_state EXCEPT 
            !services = new_services
        ]
    IN
        [ss EXCEPT 
            !sm_state = new_sm_state
        ]

(* 服务使用能力访问内存 *)
ServiceAccessMemory(ss, service_id, cap_id, size, alignment) == 
    LET
        found_service == CHOOSE s \in ss.sm_state.services : 
            s.id = service_id /\ s.running /\ (cap_id \in s.capabilities)
        
        (* 检查能力权限 *)
        has_permission == CapabilitySystem!CheckCapabilityPermission(ss.cm_state, cap_id, "memory", "write")
        
        (* 分配内存 *)
        new_mm_state == IF found_service # "" /\ has_permission THEN 
            MemoryManager!AllocatePhysicalMemory(ss.mm_state, size, alignment)
        ELSE 
            ss.mm_state
    IN
        [ss EXCEPT 
            !mm_state = new_mm_state
        ]

(* 初始化服务层 *)
InitServiceLayer(ss) == 
    LET
        (* 获取初始能力 *)
        initial_caps == CapabilitySystem!GetServiceLayerCapabilities(ss.cm_state)
        
        (* 创建内存服务并授予内存能力 *)
        with_mem_service == IF initial_caps.mem_cap # 0 THEN 
            LET
                create_result == CreateService(ss, "memory")
                mem_service_id == create_result.sm_state.next_service_id - 1
            IN
                GrantCapabilityToService(create_result, mem_service_id, initial_caps.mem_cap)
        ELSE 
            ss
        
        (* 创建进程服务并授予CPU能力 *)
        with_proc_service == IF initial_caps.cpu_cap # 0 THEN 
            LET
                create_result == CreateService(with_mem_service, "process")
                proc_service_id == create_result.sm_state.next_service_id - 1
            IN
                GrantCapabilityToService(create_result, proc_service_id, initial_caps.cpu_cap)
        ELSE 
            with_mem_service
    IN
        with_proc_service

(* 下一步状态关系 *)
Next(ss, ss') == 
    (* 创建服务操作 *)
    (\E service_type \in ServiceType : 
        ss' = CreateService(ss, service_type)
    ) \/ 
    
    (* 启动服务操作 *)
    (\E service_id \in Int : 
        ss' = StartService(ss, service_id)
    ) \/ 
    
    (* 停止服务操作 *)
    (\E service_id \in Int : 
        ss' = StopService(ss, service_id)
    ) \/ 
    
    (* 授予服务能力操作 *)
    (\E service_id \in Int, cap_id \in CapabilityId : 
        ss' = GrantCapabilityToService(ss, service_id, cap_id)
    ) \/ 
    
    (* 从服务收回能力操作 *)
    (\E service_id \in Int, cap_id \in CapabilityId : 
        ss' = RevokeCapabilityFromService(ss, service_id, cap_id)
    ) \/ 
    
    (* 服务使用能力访问内存操作 *)
    (\E service_id \in Int, cap_id \in CapabilityId, size, alignment \in Int : 
        ss' = ServiceAccessMemory(ss, service_id, cap_id, size, alignment)
    ) \/ 
    
    (* 初始化服务层操作 *)
    (ss' = InitServiceLayer(ss))

(* 系统行为 *)
Spec == Init /\ [][Next]_<<ss.mm_state, ss.cm_state, ss.sm_state>>

(* 不变式：只有运行中的服务才能访问资源 *)
OnlyRunningServicesCanAccessResources == \A s \in ss.sm_state.services, c \in s.capabilities : 
    (* 简化处理，假设访问资源的服务必须是运行中的 *)
    TRUE  (* 占位符，实际验证需要更复杂的逻辑 *)

(* 不变式：服务只能访问其被授予的资源 *)
ServicesCanOnlyAccessGrantedResources == \A s \in ss.sm_state.services : 
    (* 简化处理，假设服务只能使用其拥有的能力 *)
    TRUE  (* 占位符，实际验证需要更复杂的逻辑 *)

(* 不变式：服务层无法绕过exokernel的安全检查 *)
ServiceLayerCannotBypassSecurityChecks == 
    (* 简化处理，假设所有服务访问都通过exokernel API *)
    TRUE  (* 占位符，实际验证需要更复杂的逻辑 *)

(* 验证条件 *)
THEOREM ServiceLayerCorrectness == Spec => 
    []OnlyRunningServicesCanAccessResources /\ 
    []ServicesCanOnlyAccessGrantedResources /\ 
    []ServiceLayerCannotBypassSecurityChecks

=============================================================================